The present invention relates to an end fitting for a cable, with a cable channel extending in a connection direction towards a connection end of the end fitting, in which the cable can at least sectionwise be arranged. Furthermore, the invention relates to an enclosure assembly for connecting a cable to a mating closure, the enclosure assembly comprising a sealing enclosure with a cable volume adapted to at least sectionwise receive an end fitting for a cable, the cable volume being open at least in a connection direction, in which the enclosure assembly can be connected to the mating closure, the enclosure assembly further comprising the end fitting for the cable, the end fitting extending into the cable volume of the sealing enclosure and being affixed and sealingly connected to the sealing enclosure.
End fittings and enclosure assemblies with end fittings and sealing enclosures are known in the art. The end fitting may be shaped as a strain relief that is affixable to the enclosure, which can be attached to the mating closure. Without such a strain relief, the cable tends to slip out of the enclosure assembly, which may result in a malfunction of a plug connection comprising a connector connected to the cable.
Sealing the enclosure assembly against e.g. moisture is difficult to achieve, as an enclosure assembly having a strain relief and having sealing means is difficult to design.
Hence, known enclosure assemblies often either comprise a strain relief or sealing means or the reliability of the strain relief and/or of the sealing means is compromised by the coexistence of the strain relief and the sealing means. Therefore, the known enclosure assemblies are unreliable, as their function may be affected by humidity or by mechanical forces acting onto the cable.
In view of these disadvantages of the known enclosure assemblies, an object underlying the invention is to provide an end fitting and an enclosure assembly with improved reliability.
The object is achieved according to the invention for the end fitting mentioned in the beginning in that the end fitting is shaped with a sealing protrusion and/or a sealing groove for sealingly connecting a sealing enclosure of an enclosure assembly, the sealing protrusion and/or the sealing groove extending away from the cable channel in a radial direction of the end fitting. For the enclosure assembly mentioned in the beginning, the object is achieved according to the invention in that the end fitting is formed according to the invention and that the sealing enclosure comprises a sealing section for sealingly connecting the end fitting and a retention section for affixing the end fitting, the sealing section and the retention section being arranged one behind the other in the connection direction.
These simple solutions provide that the end fitting provides for sealing means in form of the sealing protrusion and that no separate sealing means are necessary, which may get displaced or lost. The sealing enclosure provides for a dedicated sealing section, which may in an assembled state of the enclosure assembly be sealingly connected to the sealing protrusion. Furthermore, the arrangement of the sealing section and of the retention section one behind the other in the connection direction results in a functional separation of the sealing function and the strain relief function, such that the design of the sealing section and the sealing protrusion as well of the retention section can be optimized for the respective functionality. Furthermore, as the sealing and the retention function is not to be provided by a single element, mechanical forces acting on the retention section do not negatively affect the sealing performance of the sealing section in combination with the sealing protrusion.
The solutions according to the invention can be combined as desired and further improved by the following embodiments that are in each case advantageous on their own.
According to a first possible embodiment, the sealing protrusion and/or the sealing groove may extend around the cable channel in a circumferential direction of the end fitting. Thus, the sealing protrusion and/or the sealing groove may be ring-shaped and may sealingly connect the sealing enclosure completely around the cable channel and in the circumferential direction. The sealing protrusion and/or sealing groove may be designated as fastening elements for a sealing element. The end fitting may be affixed to the sealing enclosure in a releasable manner.
In another advantageous embodiment, the sealing protrusion may comprise the sealing groove, the sealing groove having an open side that points away from the cable channel and in the radial direction of the fitting. The sealing groove may be adapted for at least sectionwise accommodating the sealing element, e.g. an O-ring, which in an unassembled state of the enclosure assembly may protrude out of the sealing groove in the radial direction. Using a sealing element like an O-ring enables that the end fitting can be produced of a material that alone may be too stiff for creating a tight sealing connection to the sealing enclosure. The stiff sealing protrusion, however, may be mechanically stable enough to position the sealing element in its sealing position. The sealing element, e.g. the O-ring may be optimized for creating a sealing connection between the end fitting and the sealing enclosure. In particular, the sealing element may be formed of an elastic material that is elastically deformable and can be brought in a humid tight contact with the end fitting and the sealing enclosure. Alternatively, the sealing element may be attached to the fastening element by a material-fit, and e.g. be co-injection-molded with the fastening element. The fastening element may be shaped such that the sealing element protrudes from the end fitting the radial direction.
In order to affix the end fitting in the sealing enclosure, the end fitting may in a further advantageous embodiment be formed with an affixing section that is adapted to be affixed to the sealing enclosure. For instance, the mechanical properties, e.g. the stiffness, and the dimensions of the affixing section may be optimized for collaborating with the retention section. The affixing section and the sealing section may be arranged one after the other in the connection direction thereby being arranged with respect to each other in order to interact with the retention section and the sealing section respectively. Such an arrangement enables to spatially separate the sealing function and the affixing function, resulting in the above mentioned advantages.
In order to be able to provide the strain relief functionality, the end fitting may be adapted to be affixed on the cable, e.g. on a sheath of the cable. For instance, the end fitting may be formed as an injection-molded part molded over the cable. Using the proper molding conditions, the end fitting adheres to the sheath and may even form a material-fit. Furthermore, injection-molding the end fitting is cheap.
In order to further improve the reliability, the end fitting may in a further advantageous embodiment be shaped as a bend protection for the cable. Dysfunctions caused by cable breaks are at least reduced by such an end fitting.
For sealingly connecting to the end fitting and in particular its sealing element, the sealing section of the sealing enclosure may in a further advantageous embodiment comprise a sealing duct with an inner sealing wall that surrounds the cable volume in the radial direction. The sealing duct may at least sectionwise be complementary to the end fitting and may in particular have a hollow cylindrical shape with the same or an only slightly greater diameter than the sealing protrusion or the sealing groove with the sealing element. In the connection direction, the sealing duct may have a length that allows for a sealing connection to the end fitting in a range of relative positions, the range extending from a position in which the end fitting has just entered the sealing duct to an end position in which the end fitting is arranged at least in the assembled state.
In the assembled state of the enclosure assembly, the sealing protrusion and/or the sealing groove of the end fitting may in a further advantageous embodiment be sealingly connected to the inner sealing wall of the sealing enclosure. In particular, the sealing protrusion and/or the sealing groove may be connected to the inner sealing wall by the sealing element, e.g. by the O-ring. The sealing element may be pressed between the sealing protrusion and the inner sealing wall and may sealingly connect the sealing protrusion and the inner sealing wall.
In order to facilitate a compact design of the enclosure assembly, the retention section may in a further advantageous embodiment be arranged at an end of the cable volume, the end facing against the contact direction. In particular when the connection end of the end fitting is provided with a plug and ends in the connection direction, the retention section at the end of the cable volume facing against the connection direction provides that mechanical forces acting onto the cable are absorbed by the sealing enclosure at entry of the cable into the sealing enclosure. Hence, the forces are not let through the sealing enclosure via the cable to the connector to a considerable extent but via the sealing enclosure to the mating closure. Furthermore, the sealing protrusion and/or the sealing groove can in the connection direction be arranged behind the retention section. Thus, also the sealing functionality is protected from mechanical forces acting onto the cable and absorbed by the retention section.
In another advantageous embodiment, the retention section may comprise a retention member with at least one resiliently deflectable holding tongue for holding the end fitting. The holding tongue may be pressed against the end fitting, thereby securing the location of the end fitting relative to the sealing enclosure by a force- or form-fit. In particular, the retention member may affix the end fitting at its affixing section relative to the sealing enclosure. The affixing section may be arranged at a distance to the sealing protrusion or at least before or behind the sealing protrusion, again separating the sealing from the affixing functionality.
The retention member may in another advantageous embodiment be an integral part of the sealing enclosure. For instance, the sealing enclosure may be an injection-molded part, which is produced simultaneously with the retention member in one shot. Hence, the sealing enclosure and the retention member can easily and at low cost be produced.
The retention member may in another advantageous embodiment be formed as a retention bushing, through which the cable volume may extend. As a bushing, the retention member may extend around the end fitting and may hold the end fitting on several sides, such that acting holding forces outweigh each other. The bushing may comprise one or several holding tongues that are equally distributed in the circumferential direction of the end fitting.
The holding tongues may be provided at their free ends or tips with a bevel-like ramp that preferably faces the cable and thus provides for a tapering cavity between the tongue and the cable, which facilitates the release of the holding tongues. By the bevel, the material thickness at the tip of the holding tongue may be reduced to less than the half of the maximum tongue thickness.
In order to be able to use the sealing enclosure with different end fittings, the retention member may in a further advantageous embodiment be shaped as a removable retention cartridge. The retention cartridge can be assembled with the sealing enclosure in the connection direction and can be exchanged against other retention cartridges with different dimensions. For instance, the sealing enclosure may be shaped with a retention section for holding the retention cartridge. The retention section of the sealing enclosure may even be designed to hold either the retention cartridge or the end fitting, such that the retention cartridge may be used as an adapter piece for the sealing enclosure for using with smaller end fittings. Alternatively, the retention cartridge may be held by the retention section by a snap connection. The retention cartridge and/or the retention section for holding the retention cartridge may be provided with one or more holding tongues that may be formed as the holding tongues of the sealing housing with the integrated retention member.
In a further advantageous embodiment, the enclosure assembly may comprise a coupling enclosure via which the sealing enclosure can be coupled to the mating closure. The coupling enclosure may furthermore act onto the at least one holding tongue and press the at least one holding tongue against the radial direction and towards the cable volume, i.e. against the end fitting or the retention cartridge in the assembled state of the enclosure assembly. The coupling enclosure may be coupled to the mating closure in a bayonet-manner.